Field of the Invention
The present invention relates to an electronic circuit for controlling the operation of a watch having analogue hands, or other means of time display such as LED's, LCD or electronic ink, as well as an integrated circuit for use in such an electronic circuit.
Description of Related Art
US 2009/135678, later on published as granted U.S. Pat. No. 8,130,596 B2, discloses an electronic circuit for controlling the operation of a watch comprising a processor for interacting with peripheral members of the watch. The circuit has initializing means to allow controllers to provide inputs and outputs of and for peripheral members of the watch. One method according to this prior art allows to switch the processor from a passive mode to an active mode, whereby the active mode allows the processor to execute instructions. The processor receives an interruption signal from at least one peripheral member of the watch, wherein said signal is transmitted to the processor via the connecting means; the processor is switched on, he executes the instruction associated with the interruption signal and places the processor again in the passive mode once the instruction has been executed or into a standby mode to reduce the overall electrical power consumption of the electronic watch circuit. One mandatory peripheral member is the system used to perform the function of a watch, either driving hands or providing a digital representation of the time.
US 2013/0303087 A1 discloses a connected device platform where different communication elements are combined. It is mentioned that this includes smart watches, connected music players, smartphones, tablet computers, and eBook readers, providing especially wireless access to different media. The document states that smart watches are reducing the power consumed by an additional radio link and would be enabled to use coin-cell batteries. These watches typically have rich interfaces and display text on the watch face. Users of these devices frequently complain that they cannot read the text on account of its small size, that the digital display is not very elegant, and that they prefer an analog watch. FIG. 3 of this prior art combines traditional analog hands and a digital display behind the analog movement.
U.S. Pat. No. 5,289,452 provides initialization means acting on the peripheral members of a watch without intervention of the processor onto the initializing means.
EP 2 541 347 A2 discloses an electronic timekeeping circuit with two power supply domains. Power is supplied to each of the power supply domains by a corresponding one of the power supplies. Timekeeping registers are duplicated for each of the power supply domains. The timekeeping registers are synchronized between the power supply domains if one of the timekeeping registers is modified or if one of the power supplies is turned off and subsequently turned back on. The timekeeping circuit uses a single piece of silicon for the system. The registers are duplicated to save power. However, each time the microprocessor wakes up, it synchronizes and sets the registers, wherein this action takes additional power. Furthermore the document is related to a RTC. A real time clock does not have motors or motor drivers and is not a chip able to drive a watch movement.
U.S. Pat. No. 5,045,988 describes an isolated adjustable frequency AC inverter control, including a low voltage microcontroller referenced to ground potential and a waveform generator coupled to the microcontroller through a serial data link including optical isolation devices. The waveform generator floats at the negative bus potential of the DC source for the inverter. The waveform generator produces switching signals for the inverter under control of the microcomputer. The waveform generator, serial communications circuitry and other support circuits are all part of a single application specific integrated circuit.
U.S. Pat. No. 6,047,380 relates to a microcontroller wake-up function for a microprocessor using an. I2C circuitry and interrupt as the microcontroller receives it, whereas the present invention which are usually not used in a watch chip.